Urban Water Systems – Pennine Water Group The University of Sheffield

Professor Simon Tait (s.tait@sheffield.ac.uk)

Pennine Water Group

• EPSRC Platform Grant - Awarded in 2001 and renewed in 2005 and again in

2010

• Most established Urban Water Group in UK, unique with second renewal of

PG

• International Track Record

• 6 Professors and their research groups – Over 50 active researchers in

water

• The Pennine Water Group has developed a holistic and integrated approach to

improving the performance of urban water that spans disciplines and crosses

international and institutional boundaries.

• The range of disciplinary expertise includes; engineering, economics

microbiology, computer science and the social sciences.

• Projects funded by EPSRC/NERC/EU FR7/EU Marie Curie/EU Interreg/Water

Industry/Investors

• Recent investment by University in new staff and facilities

Prof. David Lerner

Catchment Science

Prof. Simon Tait

Sewers and Rivers

Prof. Kirill Horoshenkov

Sensors - Acoustics

Key Water Engineering Staff at Sheffield

Prof. Joby Boxall

Water Infrastructure

Prof. Catherine Biggs

Water Process Engineering

Prof. Adrian Saul

Urban Water Engineering

Dr Songdong Shao, Particle Based Modelling, Dr Chris Keylock,

Turbulence; Dr Wernher Brevis, Shallow Flows, Dr James

Shucksmith, River Pollutant Processes; Dr Liz Sharp Social Science

- Governance, Dr Virginia Stovin, Green Infrastructure, Professor

Richard Ashley – Water Sensitive Urban Design, Dr Richard Collins

– Potable Water Systems, Dr Henriette Jensen – Biofilms, Dr

George Kesserwani – Flood Modelling/ Flash Floods, Prof Will

Zimmerman – Treatment Processes

Pennine Water Group

Research Strategy

PWG - Work Areas

Three work areas – multi-disciplinary projects

• Sustainable Integrated Systems

• New Technologies - Urban Water Engineering

• Engagement and Implementation

Sustainable Integrated Systems

Deliver tools, techniques and models which capture and

explain the complex interaction between the urban and rural

environment at a range of scales

• Automated Data Analysis - soft

computing approaches for

turning data into information

• Optimal instrumentation

location and development

• Transients for leak detection

• Dynamic behaviour of leakage

• Fixing the DRIP (data rich

information poor)

• Fuzzy diagnostics for event

detection and identification

(quantity and quality)

• Local vs. central intelligence

Leakage

PODDS: Prediction and control of Discolouration in Distribution Systems

Water Engineering ResearchUniversity of Sheffield

Department of Civil & Structural Engineeringwww.PODDS.co.uk

Water Distribution System Flushing Strategies:

Current Research ImplicationsThe PODDS approach to Water Distribution System (WDS) management is based on scientific research that has shown discolouration is a predictable response to increases in system shear stress. Applying an hydraulic shear force(τa) above the peak daily (τ’) creates an excess shear (τexcess) leading to discolouration (see figure 1). The response is a function of the strength characteristics and discolouration potential (C) of material layers attached to the pipe walls.

Material layers develop throughout the WDS with asset deterioration primarily being determined by water quality (amount of material entrained) and conditioning hydraulics. Optimal pro-active management strategies are required to maintain assets yet minimise network interventions, thus saving time, money and limit discolouration risk to customers. To achieve this pipe material needs to be considered during operational planning as material accumulation processes, layer strength characteristics and discolouration potential are different in plastic and cast iron pipes

Plastic

or smooth-walled pipes

Cast Iron

or rough-walled pipes

Figure 1 – PODDS model of layer shear strength vs. discolouration potential

1Average UK value; actual deterioration rate variable based on water quality and network hydraulics.Warning: potential discolouration risk can be posed much sooner.

2Value shown based on work in the Netherlands by KIWA.

Dr. Joby Boxall Tel: 0114 2225760

email: J.B.Boxall@Sheffield.ac.uk

Mr. Stewart Husband Tel: 0114 2225416

email: S.Husband@Sheffield.ac.uk

August 2007

Modelling has shown that a flushing induced force of 1.2 N/m2 is sufficient to

mobilise all material layers and clean pipe. MAINTENANCE

Modelling has shown that for any increase in applied shear force (e.g. flushing), material will continue to be mobilised.

"6/11

"4/5

"3/3

/6.0/2.1 2

sl

sl

sl

smmN TARGET

FLUSHING VELOCITY

Risk based value. Criteria: available flow, pipe discolouration

status and risk of unplanned hydraulic disequilibria.

4 Years

1DETERIORATION (from clean to maximum risk)

1.5 years surface water 3 years ground water

a) Research suggests a peak daily flow of 20.4m/s will promote “self-cleaning” b) Improving water quality (reduces

deterioration rate).

OPERATION

a) Higher daily flows reduce potential discolouration event magnitude.

b) Improving water quality (reduces deterioration rate).

Biofilms believed integral to cohesive layers formation; liable to ‘slough’ increasing

discolouration risk.

NOTES Corrosion by-products increase pipe

deterioration rate and ‘feed’ downstream pipes (irrespective of material).

Implementation of self-cleaning velocity criteria to maintain residential water quality (networks characterised by a branched structure with

downstream declining diameter)

NETWORK DESIGN

Not applicable

∞

∞

?

Layer Shear strength , τ (N/m2)

1.2

Dis

colo

ura

tio

n p

ote

nti

al

C (

NT

Um

)

τ’ τa

τexcess

Cplastic

Ciron

CI pipe

Plastic pipe∞

∞

?

Layer Shear strength , τ (N/m2)

1.2

Dis

colo

ura

tio

n p

ote

nti

al

C (

NT

Um

)

τ’ τa

τexcess

Cplastic

Ciron

CI pipe

Plastic pipe

Discolouration - Quantifying discolouration

impact of flow changes

- Maintain TM flexibility by

conditioning procedures

(maintenance schedules

with no water loss)

- Simulate discoloured water

event potential

Radar and rainfall forecasting – sewer network modelling

Overall, using radar or rain gauge gives similar flow simulation results, but flow peaks can be considerably different in intensity and/or timing

Differences in return periods within small area

Current rainfall measurements and hydrodynamic sewer flow model Both not accurate enough for flood prediction on individual street level

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RG4

RG5RG3

RG2

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RG5RG3

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• Case study flooding associated with sewer

sediment deposits

• Quantify uncertainty in sewer sediment transport

modelling

• Laboratory measurement of physical sewer

sediment properties + models

Systems Modelling Uncertainty

5 ‘surfaces’, one for

each different

roughness

Uncertainty in Ackers-White sediment transport equations - Ggr ratio Uncertainty due to variability input parameters (ks and d35) Predicted deposit levels - multi month rainfall time series, for sensible ranges of Ggr ratio, ks and d35 Response surface created Monte Carlo Sampling

Overall Uncertainty – Response Surface

Baseline

no of

failures

Range of failures due

to uncertainty

Water Quality Failures – Integrated Models - Uncertainty

• Focussed on diatoms

• Lab experiments on effects of

detergents and nutrients

• Field measurements of upstream to

downstream changes

• Planned:

• Field measurements of before

and after rectification

Research on ecological impacts of misconnections

Sustainable Integrated Systems

• Leakage modelling and monitoring

• Potable water quality management

• Integrated catchment modelling

• Water sensitive urban design

• Urban Rivers and Flooding – Resilience and Recovery

• 2D Flood modelling – drainage /surface interactions

• Whole life costing of urban drainage systems

• System adaptation to climate change

• Heat recovery in urban water systems

Development and Delivery of New Technologies

• To monitor, control and maximise the performance of our existing, deteriorating urban water infrastructure, and how it integrates within the wider water system.

• Three sub-themes have been identified:

bio-engineering

low-cost, adaptive sensor networks

communication, data analysis and interpretation

Development and Delivery of New Technologies

• Synthetic biology in the water industry

• Cell to cell interactions

• Micro bubble created using fluidic oscillation

• Sensor technologies – sewer and potable water systems

• Biofilm and bacteria in potable water distribution networks

• DNA based classification of in-sewer bacterial communities

Microbiology in Water Systems

• Distribution system as reactors,

not inert network of pipes

• Vast surface area, high residence times,

uncertain and variable conditions

• Physically, chemically and biologically

complex and active systems

Pipe Dreams

Internationally unique facilities

• DNA based typing of in-sewer bacterial

communities

• Seasonal and spatial effects; overflow

performance and corrosion

• Odour processes and modelling

Sewer System Characterisation

Anaerobic digesters: Micro bubbles go

where no bubble has gone before

Methanogensis:

AD does not require a gaseous nutrient, so micro bubbles of what

carrier gas?

High purity CO2 as a carrier gas produces 100% more biogas

Reduces CO2 emissions by bacteria fixing it to hydrogen, producing

methane fuel which can be recycled on the plant by producing

electricity and heat, put to the gas mains, or

Underpins EPSRC 4CU Programme Grant (£4.6m) for use as a high

energy chemical feedstock

Instrumentation – Development

• Mainly acoustic based – low power and robust –

scattering or reflection principles

• Condition monitoring – cracks/defects/blockages in

pipes – “Sewerbatt” – reflectometry – Acoustic Sensing

Technology Ltd

• Acoustic scattering devices – non-contact flow

monitoring – very accurate water depth, flow velocities

hydraulic resistance – acoustic scattering from water

surface waves

Wave probe Ultrasonics

Water surface Flow

PIV/LIF

Flow velocity/surface waves/acoustics

Still

D = 60mm D = 90mm

Experimental set-up

0 50 100 150 200-0.8

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-0.4

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1.2

Spatial lag (mm)

Corr

ela

tion c

oeff

icie

nt

(-)

Temporal cross-correlation of non-equidistant wave probes

0mm sep

30mm sep

50mm sep

70mm sep

80mm sep

90mm sep

110mm sep

120mm sep

114 115 116 117 118 119 120 121 122 123 124

73

74

75

Depth

(m

m)

Time (s)

Time series from two wave probes seperated by 30mm

0 100 200 300 400 500-1

-0.5

0

0.5

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Corr

ela

tion c

oeff

icie

nt

(-)

Probe separation (mm)

Spatial surface correlation function

- Wave gauge analysis

Surface wave analysis

Test Depth

(mm)

Flow rate

(l/s)

Mean Vel

(m/s)

Surface Vel

(m/s)

Corrected

Acoustic

Vel

(m/s)

Error

(%)

1 53 3.1 0.38 0.49 0.39 1.8

2 72 6.7 0.52 0.67 0.49 6.5

3 98 11.1 0.56 0.75 0.58 2.9

Field Prototype Devices – river and sewer pipes

• Significant uncertainty

• Magnitude

• Frequency

• Duration

• Structural impacts

• Catastrophic failure

• Long term fatigue loading?

• Water quality impacts

• Ingress

• Mobilisation of material layers,

including biofilms and

pathogens?

Occurrence and impacts of transients

Engagement and Implementation

• To change the values associated

with water, especially in association with the new energy and carbon agendas

• Economics/Governance/public engagement/planning

• Three sub-themes have been identified:

Engagement and governance

Novel technologies

Collaboration and translation

Engagement and Implementation

• Prepared – institutional adaptation to climate change

• Public participation activities

• Acoustic Sensing Technology Ltd – acoustic condition sensors

• Novel sensors to detect leakage

• Real time monitoring and control of water systems

Large EU funded

integrated project

35 partners – utilities

(water companies) and

research institutes

4 year project –

research and

application

PWG involvement -

institutional adaptation

Water Utility Partner -

DCWW

PREPARED: Cities, water & climate change adaptation

PREPARED: Cities, water & climate change adaptation

Engineering researchers

Social scientists

Welsh water practitioners

PREPARED requirement:

research AND

implementation.

Aim: ‘To help water

management become

more adaptive in Wales’

Framework

• Interviews

• Documentary analysis

Audit Tool

• Workshops

• Scenarios

Action Plan

• Evaluate action

Adaption Planning Process

Manual

Acoustic Inspection of Sewer Defects

• Acoustic – airborne monitoring –

combined sewers

• Multi frequency signal – reflection

pattern identifies defect

• Fast – no man entry

• Practicality of widespread inspection

– better asset management

Condition Defects

by CCTV

Defects* by

Acoustic Method

Acoustic vs. CCTV

(%)

Acoustic distance RMS

Difference (m)

Next manhole 24 20 83 0.21

Lateral connection 95 86 75 0.48

Crack (all types) 69 57 71 0.42

Joint - displaced 22 16 55 0.27

Total 210 179 71 0.35

• An acoustic method of condition

detection is an fast alternative to

CCTV.

• This method can detect standard

conditions such as lateral

connections, blockages, cracks and

their combinations.

• Acoustic signatures can be recorded

and stored in a database for

automatic condition detection and

recognition.

• Low power and data storage

requirements

• Equipment now commercially

available

Acoustic Inspection of Sewer Defects

• Forecasting environmental

conditions in order that the waste

water treatment works can be

controlled

• Offers reduction in energy cost /

improved water quality

Real Time Control of Treatment

Facilities – Urban Water Systems

1D Flumes + annular flume + flooding rigs

PIV/ADV/LSPIV

High speed imaging

Water quality measurement

DNA based techniques

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Monitoring time steps (5 mins interval)

Ch

am

be

r w

ate

r le

ve

l (m

m)

Model prediction output sample from Carleton Rd Skepton CSO

Prediected value

Actaully value

Chamber weir height

Chamber weir

Prediction model output sample

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Wider Engagement at Sheffield

Conclusions

• Large, well resourced multi-disciplinary group

• Broad, well integrated water R&D across

different disciplines

• Three work themes: sustainable integrated

systems, new technologies, implementation and

engagement

• Strong alignment with UK Government and EU

Strategic Priorities

• Unique facilities and able to call on a large

science base (physical and social sciences)